US 20050154442 A1
A catheter assembly comprises a catheter which includes a catheter shaft and a balloon positioned thereon. A rotatable sheath is rotatably disposed about a portion of the catheter. The rotatable sheath has a first portion inner diameter and a second portion inner diameter, which are different.
1. A catheter assembly comprising:
a catheter, the catheter comprising a catheter shaft and a balloon positioned thereon; and
a rotatable sheath, the rotatable sheath rotatably disposed about at least a portion of the catheter, the rotatable sheath having a first portion inner diameter and a second portion inner diameter, the first portion inner diameter being different than the second portion inner diameter.
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39. A catheter assembly comprising:
a catheter, the catheter comprising a catheter shaft and a balloon positioned thereon;
a rotatable sheath, the rotatable sheath rotatably disposed about at least a portion of the catheter shaft adjacent to the balloon;
a stent the stent rotatably disposed about at least a portion of the balloon; and
at least one stent engagement member, the at least one stent engagement member being actuatable from an engaged position to a released position, in the engaged position the at least one stent engagement member extending from the rotatable sheath to engage the stent, in the released position the stent being released from the at least one engagement member.
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47. A method of forming a rotatable sheath assembly for use in a stent delivery system comprising:
providing a tubular member, the tubular member having a wall which defines a tubular member inner diameter;
disposing the first tubular member about a first support mandrel, the first support mandrel having a first support mandrel outer diameter, the first support mandrel outer diameter being substantially less than the tubular member inner diameter;
pinching a portion of the wall of the tubular member together along a seam, a first portion of the tubular member on one side of the seam forming a primary lumen and a second portion of the tubular member on the other side of the seam forming a secondary lumen, the first support mandrel being positioned within the primary lumen, the primary lumen defining a primary lumen diameter, the secondary lumen defining a secondary lumen diameter; and
removing a predetermined area of the wall to form an opening in communication with the secondary lumen.
48. The method of forming a rotatable sheath assembly of
positioning a second support mandrel through the secondary guidewire lumen, the secondary support mandrel having a secondary support mandrel outer diameter,
heat setting the tubular member such that the primary lumen diameter is at least as great as the first support mandrel outer diameter and the secondary lumen is at least as great as the secondary support mandrel outer diameter;
removing the first support mandrel and the second support mandrel from the tubular member.
49. The method of forming a rotatable sheath assembly of
folding the distal region of the second portion about the first portion, such that the secondary lumen extends through the opening and through the proximal region of the second portion of the tubular member.
50. The method of forming a rotatable sheath assembly of
removing the distal region of the second portion along the seam, such that the secondary lumen extends through the opening and through the proximal region of the second portion of the tubular member.
Description of the Related Art
A stent delivery system employing a stent assembly with branches intended for deployment in the adjacent branches of a vessel bifurcation has been proposed to allow placement of a portion of the assembly in both a primary passage, such as an artery, and a secondary passage, such as a side branch artery. Additionally, these stents generally have an opening which allows for unimpeded blood flow into the side branch artery. However, problems are still encountered in orienting the stent relative to the side branch at the bifurcation of the primary and secondary passages. Moreover, such bifurcated assemblies are typically specially manufactured at an increased cost over a more standard stent intended for single vessel deployment.
In delivering a stent to a vessel location, many current devices rely on either passive torque (e.g., pushing the stent forward and allowing the stent that is fixed on the guidewire/balloon to passively rotate itself into place) or creating torque from outside of the patient to properly orient the medical device in the passage. These devices and methods of achieving proper angular orientation have not been shown to be effective in properly placing and positioning the stent.
Thus, a need exists to provide a catheter which is capable of allowing a medical device such as a stent to be easily maneuvered and aligned at a vessel bifurcation or other location, while also adequately protecting the catheter and/or balloon to which the stent is mounted. Various devices and methods described herein address this need by providing a catheter system with a rotatable sheath apparatus which a stent may be mounted on or engaged to. The rotatable assembly is rotatable about the catheter shaft thereby eliminating the need to apply torque to the catheter shaft to align the stent at a vessel bifurcation.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.
Some embodiments of the present invention include a freely rotating deployment assembly for a stent assembly for maintaining side branch access and protection.
In some embodiments the invention is directed to a rotatable catheter assembly which comprises a catheter about which a stent, prior to delivery is freely rotatable. The stent maintains its position relative to the catheter by engagement to a rotatable collar positioned proximal to the stent.
In some embodiments at least a proximal end of the stent is engaged by an engagement mechanism to the rotatable collar that is located proximal to the stent. The catheter assembly constructed and arranged to release the stent from the collar to deliver the stent. In some embodiments the engagement mechanism comprises one or more engagement members constructed from a shape memory material and/or an electro-active polymer (EAP). In some embodiments the one or more engagement members are at bio-absorbable. In some embodiments the one or more engagement members are mechanically actuatable from an engaged position, wherein the stent remains secured to the collar, to a release position, wherein the stent is freed from the collar.
In at least some embodiments the catheter comprises a balloon about which the stent is rotatably mounted prior to delivery. In some embodiments at least a portion of the balloon is coated with a lubricious substance. In some embodiments a protective covering is interposed between the balloon and the stent. In at least one embodiment the covering is an expandable layer of material.
At least one embodiment of the invention is directed to alternative configurations of rotatable sheath mechanisms such as are described in U.S. patent application Ser. No. 10/375,689, filed Feb. 27, 2003 and U.S. patent application Ser. No. 10/657,472, filed Sep. 8, 2003 both of which are entitled Rotating Balloon Expandable Sheath Bifurcation Delivery, the entire content of both being incorporated herein by reference.
In some embodiments the invention is directed to a rotatable sheath having a sheath wall having a predetermined thickness, the sheath wall defining at least one lumen which extends through at least a portion of the length of the sheath.
In some embodiments the thickness of the sheath wall is variable such that the inner diameter of the sheath is variable and/or non-circular and the outer diameter of the sheath is substantially constant and/or circular.
In some embodiments the sheath comprises one or more bands or areas of radiopaque material and/or material detectable by imaging modalities such as X-Ray, MRI or ultrasound. Such material(s) may be in the form of a coating.
In some embodiments the sheath has a nominal state wherein when the sheath is in the nominal state the outer diameter of the sheath has a first diameter that is substantially constant throughout the length of the sheath; a loading state wherein when the stent is being loaded onto the sheath the outer diameter of the sheath has a second diameter less than first diameter; and a loaded state wherein once the stent is loaded onto the sheath the outer diameter of the sheath is variable along the length of the sheath. In some embodiments, when the sheath is in the loaded state at least a first portion of the outer diameter of the sheath is in the first diameter and at least a second portion of the outer diameter of the sheath is in a third diameter. In some embodiments the third diameter is less than the first diameter and in some embodiments the third diameter is greater than the second diameter.
In at least one embodiment the invention is directed to a catheter system employing a balloon, a rotatable sheath is disposed about the balloon. In some embodiments the rotatable sheath has a length which extends over one or both cones of the balloon.
In at least one embodiment the invention is directed to a catheter system employing any of the rotatable sheath configurations described herein.
These and other embodiments which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof However, for a better understanding of the invention, its advantages and objectives obtained by its use, reference should be made to the drawings which form a further part hereof and the accompanying descriptive matter, in which there is illustrated and described a embodiments of the invention.
A detailed description of the invention is hereafter described with specific reference being made to the drawings.
While this invention may be embodied in many different forms, there are described in detail herein specific embodiments of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated.
For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated.
Referring now to the drawings which are for the purposes of illustrating embodiments of the invention only and not for purposes of limiting same,
The rotating sheath assembly 100 depicted in
Though the housing 104 may be constructed of a wide variety of materials including metal plastic, etc., in some instances the housing 104 may be an external reinforcing member or hypotube 64.
The hypotube 64 may comprise stainless steel one or more polymer materials or other material. To improve flexibility, in some cases the housing 104 is provided with one or more openings 110 along its length. For example, the housing 104 may be spiral cut to provide at least a continuous opening 110 which acts to provide improve the flexibility of the housing 104.
The assembly 100 may include a secondary guidewire housing 104 which further comprises an inner shaft 103, about which the hypotube 64 is disposed. The inner shaft 103 may be a flexible hollow tubular member which extends distally beyond the distal end of the hypotube 64. This distal and/or proximal tips 105 of the inner shaft 103 provides the housing with a flexible protective sheath about the guidewire 108 as it passes out of the secondary guidewire lumen 106. Such a protective covering prevents the guidewire 108 from excessively rubbing against the wall 201 of the vessel 199, such as in the manner depicted in
In many catheters, the shaft 144 of the catheter 116 defines a primary guidewire housing 211 through which a primary guidewire 107 may be advanced. In use, guidewires 107 and 108 are passed through a lumen or other body vessel 209 to a bifurcation 203. Primary guidewire 107 is then advanced into a primary branch of passage 205 of the bifurcation 203 while the secondary guidewire 108 is advanced into the adjacent or secondary branch 207 of the bifurcation 203. As the system is advanced along both guidewires 107 and 108, as a result of the divergent paths defined by the guidewires 107 and 108, the rotatable sleeve 104 will rotate the stent 120 into a desired position so that the secondary opening 130 a of the stent is aligned with the secondary passage 207. Where the catheter 116 is a fixed wire system, the use of the primary guidewire is unnecessary.
Examples of the rotating assembly 100 include a distal portion of the housing 104 being engaged to at least a proximal portion of the sheath 102 at an engagement site 112. The manner or mechanism of engagement between the sheath and housing 104 may be by bonding, welding, adhering adhesively engaging, mechanically engaging or otherwise connecting the surfaces of the respective sheath 102 and housing 104.
The sheath 102 is a hollow tube of sheath material that is configured to be placed over the balloon 114 or other region of a catheter 116, such as in the manner illustrated in
In order to ensure that the sheath 102 is rotatable about a balloon 114 and/or other region of a catheter, even with a stent 120 crimped on to the sheath 102 and the catheter is being advanced through the a body, the sheath 102 may be constructed of a variety of low friction materials such as PTFE, HDPE, etc. In at least one embodiment the sheath 102 is at least partially constructed of a hydrophilic material, such as hydrophilic polymers such as; TECOPHILIC® material available from Thermedics Polymer Products, a division of VIASYS Healthcare of Wilmington, Mass.; TECOTHANE®, also available from Thermedics Polymer Products; hydrophilic polyurethanes, and/or aliphatic, polyether-based thermoplastic hydrophilic polyurethane; and any other material that provides the sheath 102 with the ability to rotate freely about the balloon 114 when in the “wet” state, such as when the catheter is exposed to body fluids during advancement through a vessel. Suitable sheath materials may also provide the sheath with rotatability in the “dry”, or pre-insertion, state, but with the application of a greater amount of force than when in the wet state, such materials are referred to herein as being tecophilic.
A sheath 102 at least partially constructed from tecophilic material provides the sheath 102 with the ability to rotate freely about the balloon 114 when in the “wet” state, such as when the catheter is exposed to body fluids during advancement through a vessel. The tecophilic sheath 102 is also capable of rotation in the “dry”, or pre-insertion, state, but with the application of a greater amount of force than when in the wet state.
In some cases the sheath 102 may be constructed of one or multiple materials, in one or more layers. For example, the sheath 102 may comprise an outer layer of a softer material than that of the material used in constructing an inner layer, such as has been previously described. In some embodiments, an example of which is shown in
The composition of the sheath 102 material, whether a single, multiple layer or stripe reinforced extrusion may include essentially any appropriate polymer or other suitable materials. Some example of suitable polymers include Hydrophilic Polyurethanes, Aromatic Polyurethanes, Polycarbonate base Aliphatic Polyurethanes, Engineering polyurethane, Elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example available under the trade name PEBAX), and Silicones, Polyether-ester (for example a polyether-ester elastomer such as Arnitel available from DSM Engineering Plastics), Polyester (for example a polyester elastomer such as Hytrel available from Du Pont), or linear low density polyethylene (for example Rexell).
Example of suitable reinforcing materials whether alone or blended with other materials, mixtures or combination or copolymers include all Polyamides (for example, Durethan available from Bayer or Cristamid available from ELF Atochem), polyethylene (PE). Marlex high-density polyethylene, polyetheretherketone (PEEK), polyimide (PI), and polyetherimide (PEI), liquid crystal polymers (LCP), and Acetal (Delrin or Celcon).
Often the inner surface of the sheath 102 or the outer surface of the balloon 114 may include a coating of one or more low friction materials or include one or more low friction materials in its construction. Such a coating 401 is shown in
As mentioned above, the sheath 102 is configured to be freely rotatable about a balloon of a catheter even when a stent 120, such as is shown in
Stent 120 may be a stent, such as is shown in
When the secondary guidewire 108 and/or the secondary guidewire housing 104 is threaded through one of the cell openings 130 when the stent is positioned onto the assembly 100, such as is shown in
The modified cell opening 130 a, hereinafter referred to as secondary opening 130 a, is positioned on the stent 120 between the proximal opening 134 and the distal opening 136. The manner in which the secondary opening 130 a, the members 132 adjacent thereto, and to an extent the stent 120 itself, are modified or distorted by the position of the secondary guidewire and/or secondary guidewire housing is depicted in
It should be noted that when the stent 120 is placed on the assembly in the manner described above, the distortion of the secondary opening 130 a and the adjacent members 132 is of a minimal extent, and is provide only to allow sliding passage of the secondary guidewire 108, and if desired a distal portion of the secondary guidewire housing 104, through the secondary opening 130 a. As such, the actual size of the secondary opening 130 a may be substantially similar, or only marginally different than that of the surrounding cell openings 130.
It should also be further noted that while stent 120 may be a standard “single vessel” stent that is provided with a secondary opening 130 a in the manner described above, the stent 120 may also be a bifurcated stent having a trunk or stem portion, with one or more leg portions and/or branch openings adjacent thereto, through one of which the secondary guidewire may be passed. Such bifurcated stents and stent assemblies are well known in the art.
In some cases, the stent 120, sheath 102 or one or more portions thereof, may be configured to deliver one or more therapeutic agents to a delivery site such as within the vessel 199 or one or more areas adjacent thereto, such as shown in
To better accommodate placement of a therapeutic agent on the stent 120, in some instances one or more stent members 132, such as is shown in
In at least one embodiment, an example of which is shown in
A therapeutic agent may be a drug, a non-genetic agent, a genetic agent, etc. Some examples of suitable non-genetic therapeutic agents include but are not limited to: anti-thrombogenic agents such as heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethylketone); anti-proliferative agents such as enoxaprin, angiopeptin, monoclonal antibodies capable of blocking smooth muscle cell proliferation, hirudin, and acetylsalicylic acid; anti-inflammatory agents such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine; antineoplastic/antiproliferative/anti-miotic agents such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin and thymidine kinase inhibitors; anesthetic agents such as lidocaine, bupivacaine and ropivacaine; anti-coagulants such as D-Phe-Pro-Arg chloromethyl keton, an RGD peptide-containing compound, heparin, antithrombin compounds, platelet receptor antagonists, anti-thrombin antibodies, anti-platelet receptor antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors and tick antiplatelet peptides; vascular cell growth promoters such as growth factor inhibitors, growth factor receptor antagonists, transcriptional activators, and translational promoters, vascular cell growth inhibitors such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin; bifunctional molecules consisting of an antibody and a cytotoxin; cholesterol-lowering agents; vasodilating agents; and agents which interfere with endogenous vascoactive mechanisms, and any combinations thereof.
Where an agent includes a genetic therapeutic agent, such a genetic agent may include but is not limited to: anti-sense DNA and RNA; DNA coding for anti-sense RNA, tRNA or rRNA to replace defective or deficient endogenous molecules; angiogenic factors including growth factors such as acidic and basic fibroblast growth factors, vascular endothelial growth factor, epidermal growth factor, transforming growth factor α and β, platelet-derived endothelial growth factor, platelet-derived growth factor, tumor necrosis factor α, hepatocyte growth factor and insulin like growth factor; cell cycle inhibitors including CD inhibitors, thymidine kinase (“TK”) and other agents useful for interfering with cell proliferation; at least one of the family of bone morphogenic proteins (“BMP's”) such as BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 (Vgr-1), BMP-7 (OP-1), BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, BMP-14, BMP-15, and BMP-16. Any of BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 and BMP-7; dimeric proteins such as homodimers, heterodimers, or combinations thereof, alone or together with other molecules; molecules capable of inducing an upstream or downstream effect of a BMP such as “hedgehog” proteins, or the DNA's encoding them and any combinations thereof.
Where a therapeutic includes cellular material, the cellular material may include but is not limited to: cells of human origin (autologous or allogeneic); cells of non-human origin (xenogeneic) and any combination thereof. Some examples of cellular material include but are not limited to the following:
SP—(side population cells) These cells are thought to be some of the most primitive adult stem cells. They are isolated by a specific FACS technique utilizing the ability of SP cells to exclude Hoechst dye from the nucleus. In addition to bone marrow, SP cells have been isolated from most tissues, including: cardiac and skeletal muscle. By the more common surface protein identification these cells are Lin−, Sca-1+, c-Kit+, CD43+, CD45+, CD34−.
Lin−—(lineage negative cells) This group of cells is isolated from the bone marrow and all cells which have differentiated to a specific lineage (e.g. red blood cells) have been removed. Therefore leaving all of the stem and progenitor cells. This is beneficial because all primitive cells remain, but may reduce efficiency by including irrelevant, primitive cell types.
Lin−CD34−—Although CD34+ cells have received much attention, many articles have been published lately which suggest the most primitive bone marrow derived stem cells are CD34−.
Lin−CD34+—Presence of the cell surface protein CD34 has been used to identify hematopoietic stem cells. However, the marker is also present on progenitor cells and white blood cells of various levels of maturity.
Lin−cKit+—cKit is the cell surface receptor for stem cell factor, and therefore a logical choice for stem cell selection. Most widely studied from bone marrow sources, but have also been isolated from the heart.
MSC—(mesenchymal stem cells) Named so because ordinarily these cells differentiate into cells of mesenchymal tissues (e.g. bone, cartilage, fat), but may also differentiate into cardiomyocytes under certain conditions. Easily isolated from bone marrow and, unlike hematopoietic stem cells, proliferate in vitro. A subpopulation of MSCs has been shown to self-renew faster and have a greater potential for multipotential differentiation than the general MSC population. D. Prockop from Tulane U. is publishing in this area.
Cord Blood Cells—Derived from the blood remaining in the umbilical vein following child birth. This blood has been shown to contain a higher percentage of immature stem cells or progenitor cells. Typically, a matched donor must be found for patients, but a lower incidence of graft versus host disease compared to stem cell isolation from adult blood has been reported. Disadvantages include: insufficient cell number in small blood volumes, unforeseen congenital defects, and contamination by mother's blood which is likely not HLA matched.
Cardiac or other tissue derived stem cells—Most work to date has focused on isolating stem cells from bone marrow. This is due to extensive work in improving bone marrow transplants for chemotherapy and leukemia treatments. However, there is evidence that similar stem cells which can be identified by similar means (e.g. SP, cKit) can be isolated from other tissues (e.g. fat, cardiac muscle).
Whole bone marrow—An “it's in there” approach where whole bone marrow (filtered for bone particles) is transplanted. Benefits include: little processing, all stem and progenitor cells are present, and matrix proteins and growth factors may also be present. Downside—if one or two stem cell types are responsible for cardiac improvement they will only be present in very low numbers.
BM-MNCs—(bone marrow mononuclear cells) Separated from whole bone marrow by a density gradient centrifugation procedure, this population contains non-granular white blood cells, progenitor cells, and stem cells.
EPCs—(endothelial progenitor cells) Isolated from bone marrow based on cell surface markers, these cells will become endothelial cells. In theory, these cells will form new blood vessels when delivered to ischemic tissue.
Skeletal myoblasts—(or satellite cells) These cells are responsible for the regeneration of skeletal muscle following injury. They have the ability to fuse with other myoblasts or damaged muscle fibers. Cardiac muscle therapies assume these cells can integrate into the host tissue and improve tissue properties or functionally participate in contraction.
MDCs—(muscle derived cells) A population of cells isolated from adult skeletal muscle which are similar to myoblasts. The isolation technique preplating entails collecting cells which attach to culture dishes at different times after biopsy. Cells with the best potential plate in the 6th group and takes several days to obtain. Investigators working with these cells claim they are a refined population of myoblasts and should result in higher engraftment efficiencies and efficacious procedures.
Go cells—Recently isolated from adult skeletal muscle, these non-satellite cells express GATA-4 and, under certain in vitro growth conditions, progress to spontaneously beating cardiomyocyte-like cells.
Endothelial cells—Transplantation of autologous endothelial cells along with a fibrin matrix induced angiogenesis and improved cardiac function in an ischemic sheep model.
Fibroblasts—Easily obtained from adult tissues, fibroblasts may provide growth factors or participate in the would healing response. Fibroblast play a critical role in wound healing; the synthesis and deposition of extracellular matrix. Fibroblasts commonly become contractile in wound healing environments.
Smooth muscle cells—Isolated from arteries, these cells may participate or encourage angiogenesis and/or beneficial cardiac remodeling following MI.
MSCs+5-aza—Culture of mesenchymal stem cells with 5-aza forces differentiation into cardiomyocytes. These cells beat spontaneously after treatment.
Adult cardiac fibroblasts+5-aza—In theory, in vitro treatment of cardiac fibroblasts with 5-aza will result in differentiation into myogenic cells.
Genetically modified cells—Isolation of cells from the patient and genetically modifying them in vitro to encourage production of proteins or differentiation into a cell type which will be beneficial for treating heart failure.
Tissue engineered grafts—Isolation of cells from the patient which are then seeded onto and cultured within resorbable scaffolds (e.g. collagen, PLGA). These cell seeded constructs are then implanted into the patient.
MyoD scar fibroblasts—MyoD family of transcription factors prompt skeletal muscle cell differentiation in fibroblasts. Procedure involves isolation of cardiac scar fibroblasts, genetic transfection with MyoD in vitro and delivery of the cells to the heart to encourage myogenesis.
Pacing cells—Genetically modified fibroblasts which become electrically conducting and signal generators.
Embryonic stem cell clones—Use of cloning technology to produce cardiomyocytes, progenitors, or stem cells which are genetically identical to the patient.
Embryonic stem cells—These cells are the most primitive of cells and will differentiate into functional cardiomyocytes under certain conditions. Both political and technological hurdles must be overcome before commercialization of this technology.
Fetal or neonatal cells—Isolated from the heart of donors, these cells may incorporate into host tissue without immune rejection. Some cardiomyocyte progenitor cells must be present due to the continued growth of the heart in fetal and neonatal humans.
Immunologically masked cells—Allogeneic cell sources (e.g. donor cardiomyocytes) are currently unfeasible due to immune rejection. However, masking technologies have been developed which could make this technology feasible.
Tissue engineered grafts—Isolation of cells from a donor which are then seeded onto and cultured within resorbable scaffolds (e.g. collagen, PLGA). These cell seeded constructs are then implanted into the host or recipient.
Genetically modified cells—Isolation of cells from a donor and genetically modifying them in vitro to encourage production of proteins or differentiation into a cell type which will be beneficial for treating heart failure. The modified cells will then be transplanted into the host or patient.
Teratoma derived cells—A teratocarcinoma is a form of cancer in which the tumor is composed of a heterogeneous mixture of tissues. Through isolation of cells from this tumor and in vitro manipulation and culture a neuronal cell line has been developed. Layton Biosciences has successfully used these cells to form new brain tissue in stroke patients. Similar techniques may be used to produce a myogenic cell line.
Where a therapeutic agent comprises at least one polymer agent or coating, the at least one coating may include but is not limited to: polycarboxylic acids; cellulosic polymers, including cellulose acetate and cellulose nitrate; gelatin; polyvinylpyrrolidone; cross-linked polyvinylpyrrolidone; polyanhydrides including maleic anhydride polymers; polyamides; polyvinyl alcohols; copolymers of vinyl monomers such as EVA; polyvinyl ethers; polyvinyl aromatics; polyethylene oxides; glycosaminoglycans; polysaccharides; polyesters including polyethylene terephthalate; polyacrylamides; polyethers; polyether sulfone; polycarbonate; polyalkylenes including polypropylene, polyethylene and high molecular weight polyethylene; halogenated polyalkylenes including polytetrafluoroethylene; polyurethanes; polyorthoesters; proteins; polypeptides; silicones; siloxane polymers; polylactic acid; polyglycolic acid; polycaprolactone; polyhydroxybutyrate valerate and blends and copolymers thereof; coatings from polymer dispersions such as polyurethane dispersions (BAYHDROL®, etc.), fibrin, collagen and derivatives thereof; polysaccharides such as celluloses, starches, dextrans, alginates and derivatives; hyaluronic acid; squalene emulsions; polyacrylic acid, a copolymer of polylactic acid and polycaprolactone; medical-grade biodegradable materials such as PGA-TMC, Tyrosine-Derived Polycarbonates and arylates; polycaprolactone co butyl acrylate and other co polymers; Poly-L-lactic acid blends with DL-Lactic Acid; Poly(lactic acid-co-glycolic acid); polycaprolactone co PLA; polycaprolactone co butyl acrylate and other copolymers; Tyrosine-Derived Polycarbonates and arylate; poly amino acid; polyphosphazenes; polyiminocarbonates; polydimethyltrimethylcarbonates; biodegradable CA/PO4 's; cyanoacrylate; 50/50 DLPLG; polydioxanone; polypropylene fumarate; polydepsipeptides; macromolecules such as chitosan and Hydroxylpropylmethylcellulose; surface erodible material; maleic anhydride copolymers; zinc-calcium phosphate; amorphous polyanhydrides; sugar; carbohydrate; gelatin; biodegradable polymers; and polymers dissolvable in bodily fluids; and any combinations thereof.
In some instances a suitable polymer agent or coating comprises block copolymers comprising at least one A block and at least one B block The A blocks are preferably soft elastomeric blocks, which are based upon one or more polyolefins, or other polymer with a glass transition temperature at or below room temperature. For example, the A blocks can be polyolefinic blocks having alternating quaternary and secondary carbons of the general formulation: —(CRR′—CH2)n—, where R and R′ are, independently, linear or branched aliphatic groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl and so forth, or represent cyclic aliphatic groups such as cyclohexane, cyclopentane, and the like, either with or without pendant groups. Preferred polyolefinic blocks include polymeric blocks of isobutylene,
The B blocks are preferably hard thermoplastic blocks with glass transition temperatures significantly higher than the elastomeric A blocks which, when combined with the soft A blocks, are capable of, inter alia, altering or adjusting the hardness of the resulting copolymer to achieve a desired combination of qualities. Examples of B blocks include polymers of methacrylates or polymers of vinyl aromatics. More specific examples of B blocks include blocks that are (a) formed from monomers of styrene
The block copolymers are provided in a variety of architectures, including cyclic, linear, and branched architectures. Branched architectures include star-shaped architectures (e.g., architectures in which three or more chains emanate from a single region), comb architectures (e.g., copolymers having a main chain and a plurality of side chains), and dendritic architectures (including arborescent or hyperbranched copolymers).
Some specific examples of such block copolymers include the following: (a) BA (linear diblock), (b) BAB or ABA (linear triblock), (c) B(AB)n or A(BA)n (linear alternating block), or (d) X-(AB)n or X-(BA)n (includes diblock, triblock and other radial block copolymers), where n is a positive whole number and X is a starting seed, or initiator, molecule. One specific group of polymers have X-(AB)n structures, which are frequently referred to as diblock copolymers and triblock copolymers where n=1 and n=2, respectively (this terminology disregards the presence of the starting seed molecule, for example, treating A-X-A as a single A block, with the triblock therefore denoted as BAB). A particularly beneficial polymer from this group is polystyrene-polyisobutylene-polystyrene triblock copolymer (SIBS). Where n=3 or more, these structures are commonly referred to as star-shaped block copolymers. Other examples of block polymers include branched block copolymers such as dendritic block copolymers, wherein at least one of the A and B blocks is branched, for instance, where the A blocks are branched and are capped by the B blocks.
Once the stent 120 is positioned on the assembly 100, such as in the manner shown in
The collar 150 is engaged to the proximal portion 140 of the secondary guidewire housing 104 by any engagement mechanism desired, such as welding, bonding, mechanical engagement, adhesive engagement, etc. As shown in
Collar 150 may be a substantially cylindrical member that is disposed about the shaft 144 of the catheter 116 at a position proximal of the balloon 114. The collar 150 may be characterized as defining a catheter shaft lumen 146 through which the catheter shaft 144 is passed. In order to provide the collar 150 with the ability to freely rotate about the catheter shaft 144, the collar 150 defines a catheter shaft lumen 146 which has a diameter greater than the outer diameter of the shaft 144. In some embodiments one or more lubricious substances may be placed between the collar 150 and the shaft 144 to further encourage free rotation therebetween.
While the rotating collar 150 is free to rotate about the shaft 144, in some embodiments it will also be capable of being longitudinally displaced along the shaft 144 as well. As such, in some embodiments one or more locks or hubs 152 may be affixed about the shaft 144 on one or both sides of the collar 150 to prevent or limit the potential longitudinal displacement of the collar 150 relative to the shaft 144. In some embodiments the use of hubs 152 may be avoided or supplemented by providing the catheter shaft 144 with an annular protrusion or ring 139 which the collar 150 may be disposed about to prevent the assembly 100 from experiencing substantial longitudinal migration.
In at least one embodiment, an example of which is shown in
In some embodiments, end portions 121 and 123 may be constructed of a material different from that of the intermediate portion 125. In at least one embodiment one or both end portions 121 and 123 are at least partially constructed of a material having a higher hardness or durometer value than that of the material from which the intermediate portion 125 is primarily constructed.
A sheath 102 having end portions 121 and 123 may be utilized with other longitudinal position retention devices such as hubs 152 as discussed above. However, because the sheath 102 may provide the assembly 100 with the desired longitudinal securement about the catheter 116 the use of retaining hubs may be avoided if desired.
In some embodiments the assembly 100 and particularly the sheath 102 may be provided with one or more marker areas or bands 135. Bands 135 may be integral to the construction of the sheath 102 or other portion of the assembly 100 or they may be distinct components and/or coatings that are placed on, about, or within a portion of the assembly 100 following or during its construction. A marker band will typically be at least partially constructed of a material having a higher degree of radiopacity than the material from which the remainder of the assembly 100 is constructed. Such radiopaque materials include gold, platinum, chrome cobalt alloy, etc. In some embodiments the marker bands 135 are at least partially constructed of a material detectable by imaging modalities such as X-Ray, MRI or ultrasound. In at least one embodiment a marker band 135 or the sheath 102 include air voids to ease detection by ultrasound.
In some embodiments such as in the examples shown in
In some embodiments at least a portion of the secondary guidewire housing 104 includes a marker band 135.
As has been discussed above, in some embodiments the assembly 100 is provided with a sheath 102 which is configured to be able to freely rotate about a balloon 114 or other portion of a catheter 116. To provide improved rotational freedom, in some embodiments, such as in the examples shown in
In some embodiments the engagement between the sheath 102 and the balloon 114 is limited by providing the sheath 102 with a variable thickness 141 that provides the inner surface 143 of the sheath 102 with a variable diameter. As shown in
In some embodiments of the invention, an example of which is depicted in
Lumens 106 may be formed as an integral part of the wall 151 by molding or otherwise directly forming the lumens 106 into the wall 151 during manufacture of the sheath 102. Alternatively, a lumen 106 may be formed by cutting, ablating, boring or otherwise removing material from the wall 151 in order to form the lumen 106 and openings.
Each lumen 106 includes a proximal opening 155 and at least one distal opening 157 in communication therewith. Openings 155 and 157 may be present on the wall's cross-sectional end surface 159, the inner surface 143 and/or the outer surface 161 in order to provide a secondary guidewire 108 with a variety of lumen entrance and exit options.
Each lumen 106 may have a length which extends through the entire longitudinal length of the sheath 102 or only a portion thereof.
As depicted in
By including the secondary guidewire lumen 106 directly into the wall 151 of the sheath 102, the profile of the assembly is desirably reduced. As indicated above, in some procedures where the stent 120 is to be deployed at a vessel bifurcation, such as depicted in
However, it is also noted that an alternative method may be used to provide the assembly 100 with a separate guide wire lumen 106 that is distinct from the primary lumen 153 of the sheath 102, but which is also not an integral passage through the wall 151 of the sheath 102. Such a method is depicted in
At some point, one or more holes or openings, such as is depicted in
As shown in
In some embodiments the sheath 102 is heat set before the mandrels 163 and 169 are removed.
The portion of the radial flap 165 that is distal of the distal opening 157 may be cut away from the sheath 102 along the seam 167 or simply folded underneath the stent 120, when the stent 120 is disposed about the sheath 102 as in the manner shown in
Though the secondary guidewire may be passed directly through the secondary guidewire lumen 106 depicted in
Typically, when producing a system 300, such as is depicted in
In at least one embodiment, an example of which is depicted in
In some embodiments the stent 120 is disposed about the sheath 102, the combined sheath and stent may be placed in a ‘clam shell’ or other assembly which restricts radial expansion of the stent, and then the sheath is expanded by balloon or other device in order to form a more distinct interface between the raised portion 175 and the cells 130.
In some embodiments, when a pre-crimped stent 120 is mounted on a rotatable sheath 102 such as in the manner shown in
While edge protection of the stent 120 is desirable, it is also desirable to provide the system 300 with reduced profile. In at least one embodiment the profile of the system 300 is reduced by providing a mechanism which allows the stent 120 to rotate directly about the catheter 116 without the need for the rotatable sheath 102 between the balloon 114 and the stent 120. Examples of some embodiments, wherein the rotatable sheath 102 is not positioned under the stent 120 are depicted in
As is shown in
In order to provide the reduced diameter stent 120 with the capacity to freely rotate about the catheter shaft 144 and/or balloon 114 the stent 120, prior to delivery, has a diameter which is greater than that of the catheter shaft 144 and/or balloon 114. As a consequence however, the stent 120 is free to migrate longitudinally along the catheter 116. In order to prevent such migration or dislocation the sheath 102 is engaged to the stent 120. As shown in
Engagement members 172 may be constructed of any material desired, but are preferably constructed of one or more biocompatible polymers and/or metals. Engagement members 172 have a proximal end portion 174 which is engaged to the sheath 102. A distal end 176 is releasably engaged to one or more struts 132 of the stent 120. During advancement of the system 300 the distal ends 176 of the engagement members 172 are engaged to the stent 120 thereby preventing the stent 120 from being longitudinally displaced relative to the catheter shaft 144. When the stent 120 is expanded for deployment, the distal ends 176 release the stent such as in the manner depicted in
The engagement members 172 may be at least partially bio-absorbable and thus configured to release the stent 120 upon absorption of the members 172 by the body.
The engagement members 172 may be mechanically actuatable from an engaged position, wherein the stent 120 is retained to the sheath 102, such as in the manner shown in
In some embodiments the engagement members 172 are at least partially constructed from an EAP material, such as polypyrole, carbon nanotubes (i.e. ‘Bucky paper’), etc. Such members are actuatable from the engaged position to the unengaged position by transmitting an electric signal to the engagement members. Such a signal may be transmitted along a conductive catheter shaft 144, or a conductive member included therewith, to the sheath 102 and eventually to the engagement members 172. In such an embodiment the sheath 102 may also include a conductive material in its construction in order to facilitate transmission of the electric signal to the EAP of the engagement members 172.
In some embodiments, such as in the example shown in
The invention has been described with reference to the embodiments. Obviously, modifications and alterations will occur to others upon a reading and understanding of this specification. For example, the illustrated embodiments use a balloon to expand the stent although, as briefly noted above, a self expanding, self deploying or hybrid expandable stent can be used without departing from the features of the present invention. The invention is intended to include all such modifications and alterations thereof. Furthermore, it is noted that the various embodiments shown and described in U.S. patent application Ser. No. 10/375,689, filed Feb. 27, 2003 and U.S. patent application Ser. No. 10/657,472, filed Sep. 8, 2003, both of which are entitled Rotating Balloon Expandable Sheath Bifurcation Delivery, may be incorporated and/or utilized with the various embodiments described herein.
The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims.
Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim 1 should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below.
With this description, those skilled in the art may recognize other equivalents to the specific embodiment described herein. Such equivalents are intended to be encompassed by the claims attached hereto.